The Last Stand's final battle was supposed to take place in Washington, DC. Singer could very well mean they're scouting locations in Washington state.

If they wanted to have a Pacific North West (ie. Washington State) scene then I'm sure they would film that in Vancouver and have it stand in for Washington State. It's just cheaper that way. That Seattle Waterfront scene at the end of in Mission Impossible Ghost Protocol? Vancouver. The entirety of Twilights (except part 1) that was supposed to be Oregon (at least what I'm told...I would not watch that trash! )? Vancouver. Heck the high school in those movies is my high school! *sigh*